Still one of the great memories for a ton of years ago.
Only time "I" got dolphins around my boat was in late summer about 30 miles west of Smith Island (you Puget Sounders know where that is). Doing our 'orbit' in the Coast Guard cutter waiting for some thing to happen (nothing did) but lots of large shipping in the area.
Flat calm/full moon and all but what could only be called a 'ground fog' came up; couldn't have been more than 20-30 foot above the water. But enough to totally obscure a small vessel.
As an additional safety messure I turned on the mast strob light ... you can see these things for miles! All I can think is the flashing light attracted the critters who congrigated around the boat and 'did their thing.'
WONDERFUL TO WATCH!!!!